TypeConverter.kt

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package androidx.room

/**
 * Marks a method as a type converter. A class can have as many @TypeConverter methods as it needs.
 *
 * Each converter method should receive 1 parameter and have non-void return type.
 *
 * ```
 * // example converter for java.util.Date
 * public class Converters {
 *     @TypeConverter
 *     public fun fromTimestamp(value: Long): Date {
 *         return value == null ? null : Date(value)
 *     }
 *
 *     @TypeConverter
 *     public fun dateToTimestamp(date: Date): Long {
 *         if (date == null) {
 *             return null
 *         } else {
 *             return date.getTime()
 *         }
 *     }
 * }
 * ```
 *
 * @see [TypeConverters]
 */
@Target(AnnotationTarget.FUNCTION)
@Retention(AnnotationRetention.BINARY)
public annotation class TypeConverter